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    <title>Document</title>
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    <script>
      // 高级API，需要npm install ws socket.io(一般使用它解决兼容问题)
      // http 意向协议 socket 双向协议
      let socket = new WebSocket("ws://localhost:3000");
      socket.onopen = function () {
        socket.send("我爱你");
      };
      socket.onmessage = function (e) {
        console.log(e.data);
      };
    </script>
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